A Science Student Asks You Why There Are a Lower

A science student asks you why there are a lower number of unique genes compared to mRNAs. The most accurate explanation is

A) introns can be spliced together in multiple ways making variable mRNA sequences.
B) splicing both introns and exons creates variable forms of mRNA.
C) alternative splicing add introns to exons in multiple ways forming more types of mRNA.
D) exons are alternatively spliced creating many more mRNAs than genes.